]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-chdlc.c
Handle very large -f files by rejecting them.
[tcpdump] / print-chdlc.c
index b416991c1ee277656d4b3357020899f1289b38a0..24acfbd2e86c94ed85983d01181740831fa1f1e1 100644 (file)
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-chdlc.c,v 1.21 2002-10-18 20:08:34 hannes Exp $ (LBL)";
-#endif
+/* \summary: Cisco HDLC printer */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
-
-#include <pcap.h>
-#include <stdio.h>
+#include <netdissect-stdinc.h>
 
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
 #include "ethertype.h"
 #include "extract.h"
-#include "ppp.h"
 #include "chdlc.h"
 
-static void chdlc_slarp_print(const u_char *, u_int);
+static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int);
+
+static const struct tok chdlc_cast_values[] = {
+    { CHDLC_UNICAST, "unicast" },
+    { CHDLC_BCAST, "bcast" },
+    { 0, NULL}
+};
+
 
 /* Standard CHDLC printer */
-void
-chdlc_if_print(u_char *user _U_, const struct pcap_pkthdr *h,
-            register const u_char *p)
+u_int
+chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, register const u_char *p)
 {
-       register u_int length = h->len;
-       register u_int caplen = h->caplen;
-
-       ++infodelay;
-       ts_print(&h->ts);
-
-       /*
-        * Some printers want to get back at the link level addresses,
-        * and/or check that they're not walking off the end of the packet.
-        * Rather than pass them all the way down, we set these globals.
-        */
-       packetp = p;
-       snapend = p + caplen;
-
-       chdlc_print(p, length, caplen);
-
-       putchar('\n');
-       --infodelay;
-       if (infoprint)
-               info(0);
+       return chdlc_print(ndo, p, h->len);
 }
 
-void
-chdlc_print(register const u_char *p, u_int length, u_int caplen)
+u_int
+chdlc_print(netdissect_options *ndo, register const u_char *p, u_int length)
 {
-       const struct ip *ip;
        u_int proto;
+       const u_char *bp = p;
 
-       if (caplen < CHDLC_HDRLEN) {
-               printf("[|chdlc]");
-               return;
-       }
-
+       if (length < CHDLC_HDRLEN)
+               goto trunc;
+       ND_TCHECK2(*p, CHDLC_HDRLEN);
        proto = EXTRACT_16BITS(&p[2]);
-       if (eflag) {
-               switch (p[0]) {
-               case CHDLC_UNICAST:
-                       printf("unicast ");
-                       break;
-               case CHDLC_BCAST:
-                       printf("bcast ");
-                       break;
-               default:
-                       printf("0x%02x ", p[0]);
-                       break;
-               }
-               printf("%d %04x: ", length, proto);
+       if (ndo->ndo_eflag) {
+                ND_PRINT((ndo, "%s, ethertype %s (0x%04x), length %u: ",
+                       tok2str(chdlc_cast_values, "0x%02x", p[0]),
+                       tok2str(ethertype_values, "Unknown", proto),
+                       proto,
+                       length));
        }
 
        length -= CHDLC_HDRLEN;
-       ip = (const struct ip *)(p + CHDLC_HDRLEN);
+       p += CHDLC_HDRLEN;
+
        switch (proto) {
        case ETHERTYPE_IP:
-               ip_print((const u_char *)ip, length);
+               ip_print(ndo, p, length);
                break;
-#ifdef INET6
        case ETHERTYPE_IPV6:
-               ip6_print((const u_char *)ip, length);
+               ip6_print(ndo, p, length);
                break;
-#endif
        case CHDLC_TYPE_SLARP:
-               chdlc_slarp_print((const u_char *)ip, length);
+               chdlc_slarp_print(ndo, p, length);
                break;
 #if 0
        case CHDLC_TYPE_CDP:
-               chdlc_cdp_print((const u_char *)ip, length);
+               chdlc_cdp_print(p, length);
                break;
 #endif
         case ETHERTYPE_MPLS:
         case ETHERTYPE_MPLS_MULTI:
-                mpls_print((const u_char *)(ip), length);
+                mpls_print(ndo, p, length);
                break;
         case ETHERTYPE_ISO:
-                /* is the fudge byte set ? if yes lets skip a byte */
-                if (*(p+CHDLC_HDRLEN) == 0)
-                    isoclns_print(p+CHDLC_HDRLEN+1, length-1, length-1, NULL, NULL);
+                /* is the fudge byte set ? lets verify by spotting ISO headers */
+                if (length < 2)
+                    goto trunc;
+                ND_TCHECK_16BITS(p);
+                if (*(p+1) == 0x81 ||
+                    *(p+1) == 0x82 ||
+                    *(p+1) == 0x83)
+                    isoclns_print(ndo, p + 1, length - 1);
                 else
-                    isoclns_print(p+CHDLC_HDRLEN, length, length, NULL, NULL);
+                    isoclns_print(ndo, p, length);
                 break;
        default:
-                printf("unknown CHDLC protocol (0x%04x)", proto);
+                if (!ndo->ndo_eflag)
+                        ND_PRINT((ndo, "unknown CHDLC protocol (0x%04x)", proto));
                 break;
        }
-       if (xflag)
-               default_print((const u_char *)ip, caplen - CHDLC_HDRLEN);
+
+       return (CHDLC_HDRLEN);
+
+trunc:
+       ND_PRINT((ndo, "[|chdlc]"));
+       return ndo->ndo_snapend - bp;
 }
 
+/*
+ * The fixed-length portion of a SLARP packet.
+ */
 struct cisco_slarp {
-       u_int32_t code;
+       uint8_t code[4];
 #define SLARP_REQUEST  0
 #define SLARP_REPLY    1
 #define SLARP_KEEPALIVE        2
        union {
                struct {
-                       struct in_addr addr;
-                       struct in_addr mask;
-                       u_int16_t unused[3];
+                       uint8_t addr[4];
+                       uint8_t mask[4];
                } addr;
                struct {
-                       u_int32_t myseq;
-                       u_int32_t yourseq;
-                       u_int16_t rel;
-                       u_int16_t t1;
-                       u_int16_t t2;
+                       uint8_t myseq[4];
+                       uint8_t yourseq[4];
+                       uint8_t rel[2];
                } keep;
        } un;
 };
 
-#define SLARP_LEN      18
+#define SLARP_MIN_LEN  14
+#define SLARP_MAX_LEN  18
 
 static void
-chdlc_slarp_print(const u_char *cp, u_int length)
+chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length)
 {
        const struct cisco_slarp *slarp;
+        u_int sec,min,hrs,days;
 
-       if (length < SLARP_LEN) {
-               printf("[|slarp]");
-               return;
-       }
+       ND_PRINT((ndo, "SLARP (length: %u), ",length));
+       if (length < SLARP_MIN_LEN)
+               goto trunc;
 
        slarp = (const struct cisco_slarp *)cp;
-        printf("SLARP (length: %u), ",length);
-       switch (ntohl(slarp->code)) {
+       ND_TCHECK2(*slarp, SLARP_MIN_LEN);
+       switch (EXTRACT_32BITS(&slarp->code)) {
        case SLARP_REQUEST:
-               printf("request");
-                /* ok we do not know it - but lets at least dump it */
-                print_unknown_data(cp+4,"\n\t",length-4);
+               ND_PRINT((ndo, "request"));
+               /*
+                * At least according to William "Chops" Westfield's
+                * message in
+                *
+                *      http://www.nethelp.no/net/cisco-hdlc.txt
+                *
+                * the address and mask aren't used in requests -
+                * they're just zero.
+                */
                break;
        case SLARP_REPLY:
-               printf("reply %s/%s",
-                       ipaddr_string(&slarp->un.addr.addr),
-                       ipaddr_string(&slarp->un.addr.mask));
+               ND_PRINT((ndo, "reply %s/%s",
+                       ipaddr_string(ndo, &slarp->un.addr.addr),
+                       ipaddr_string(ndo, &slarp->un.addr.mask)));
                break;
        case SLARP_KEEPALIVE:
-               printf("keepalive: mineseen=0x%08x yourseen=0x%08x ",
-                       (u_int32_t)ntohl(slarp->un.keep.myseq),
-                       (u_int32_t)ntohl(slarp->un.keep.yourseq));
-               printf("reliability=0x%04x t1=%d.%d",
-                       ntohs(slarp->un.keep.rel), ntohs(slarp->un.keep.t1),
-                       ntohs(slarp->un.keep.t2));
+               ND_PRINT((ndo, "keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x",
+                       EXTRACT_32BITS(&slarp->un.keep.myseq),
+                       EXTRACT_32BITS(&slarp->un.keep.yourseq),
+                       EXTRACT_16BITS(&slarp->un.keep.rel)));
+
+                if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */
+                        cp += SLARP_MIN_LEN;
+                        ND_TCHECK2(*cp, 4);
+                        sec = EXTRACT_32BITS(cp) / 1000;
+                        min = sec / 60; sec -= min * 60;
+                        hrs = min / 60; min -= hrs * 60;
+                        days = hrs / 24; hrs -= days * 24;
+                        ND_PRINT((ndo, ", link uptime=%ud%uh%um%us",days,hrs,min,sec));
+                }
                break;
        default:
-               printf("0x%02x unknown", (u_int32_t)ntohl(slarp->code));
-                if (vflag <= 1)
-                    print_unknown_data(cp+4,"\n\t",length-4);
+               ND_PRINT((ndo, "0x%02x unknown", EXTRACT_32BITS(&slarp->code)));
+                if (ndo->ndo_vflag <= 1)
+                    print_unknown_data(ndo,cp+4,"\n\t",length-4);
                break;
        }
 
-       if (SLARP_LEN < length && vflag)
-               printf(", (trailing junk: %d bytes)", length - SLARP_LEN);
-        if (vflag > 1)
-            print_unknown_data(cp+4,"\n\t",length-4);
+       if (SLARP_MAX_LEN < length && ndo->ndo_vflag)
+               ND_PRINT((ndo, ", (trailing junk: %d bytes)", length - SLARP_MAX_LEN));
+        if (ndo->ndo_vflag > 1)
+            print_unknown_data(ndo,cp+4,"\n\t",length-4);
+       return;
+
+trunc:
+       ND_PRINT((ndo, "[|slarp]"));
 }
+
+
+/*
+ * Local Variables:
+ * c-style: whitesmith
+ * c-basic-offset: 8
+ * End:
+ */